1. Field of the Invention
The present invention relates to an RFID (Radio Frequency IDentification) tag through which information is exchanged with external equipment in a non-contact manner. The “RFID tag” used in the specification of the present application is called a “radio IC tag” by persons skilled in the technical field of the application in some cases.
2. Description of the Related Art
In recent years, there are proposed various RFID tags through which information is exchanged with external equipment such as a reader/writer in a non-contact manner utilizing radio wave (see Japanese Patent Application Laid-open Nos. 2000-311226, 2000-200332 and 2001-351082, for example). As one kind of such RFID tags, there is proposed an RFID tag in which an antenna pattern, which is a conductor pattern for radio communication, and a circuit chip connected to the antenna pattern are provided on a base sheet made of plastic or paper. Applications for the RFID tag of this type includes the one in which the tag is attached to an article and the article is identified by exchanging information concerning the article with the external equipment.
Among the applications for the RFID tag, there is one in which the tag is attached to an article which is prone to deform such as clothing. In such a using style, since the base is prone to be bent but the circuit chip is less prone to be bent, a bending stress is applied to the circuit chip, and there is a serious problem that the circuit chip is broken or circuit chip is peeled off. Hence, there is conventionally proposed a technique in which the circuit chip is covered with a hard reinforcing body including a peripheral portion of the circuit chip, thereby preventing a deformation of an RFID tag from expanding to the periphery of the circuit chip, and reducing the bending stress applied to the circuit chip.
However, according to the RFID tag using the reinforcing body, although the bending stress applied to the circuit chip is reduced, the bending stress easily concentrates on a periphery of an edge of the reinforcing body. Thus, if the RFID tag is bent many times, the antenna pattern near the reinforcing body is broken and a function as an antenna is deteriorated. Thus, it is desired to enhance the durability of the RFID tag using the reinforcing body against the bending stress.
In view of the above circumstances, the present invention provides an RFID tag having endurance against the bending stress.